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Falcon 1/4 scale Tiger Moth

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Percy Verance26/08/2014 15:43:21
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8108 forum posts
155 photos

That rare find Trevor, a countersink for steel. Or is it? Most of those I've found have been for wood, but I did eventually get one for metal.

Trevor Rushton26/08/2014 22:25:05
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458 forum posts
181 photos

Well Percy, it was certainly sold to me as such, and it does the job - at the moment at least. Perhaps you are right though, a search throws up a number of variations for metal countersinks - these seem to have a slightly different cutting pattern. Anyway I don't want to use anything too rapid in cutting for fear of going right through the fitting.

Spent a bit of time looking for info on that spruce glue problem - some quite interesting stuff out there although I have not found anything on long term decay issues. There could be some similarities with the glues used by instrument makers - I did start building a violin a few years ago and was using animal glue for that - a spruce back if I remember rightly and a real pain to plane the contact surfaces really flat. It's still largely in bits though and I doubt that it will fly.

No progress tonight, earning a living has got in the way.

Trevor Rushton02/09/2014 21:30:53
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458 forum posts
181 photos

image.jpgThe fuselage is taking shape now and has 3 dimensional form. Have partly glued the first two 1/4 ply formers and have been dry fitting the remainder. Need to proceed cautiously now as the order of assembly is critical.

The fit of the parts continues to be very good although I suggest that a couple of passes of a 1/4 and (as appropriate) 1/8 Permagrit makes fitting very easy. Mostly you can assemble the main formers dry as in the photos that follow.

of course one can't resist the entirely pointless process of putting things like the pilot in for a trial fitting! Tiger Terry weighs in at 169g and looks very comfortable in his new office.

Trevor Rushton02/09/2014 21:31:58
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458 forum posts
181 photos

image.jpg

Edited By Trevor Rushton on 02/09/2014 21:32:37

Trevor Rushton02/09/2014 21:37:05
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458 forum posts
181 photos

Don't try building the model without a couple of Permagrit tools; the 1/4 inch file is particularly useful.

Trevor Rushton02/09/2014 21:39:55
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458 forum posts
181 photos

image.jpg

Trevor Rushton02/09/2014 21:44:58
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458 forum posts
181 photos

The bottom rear spar fixing is made up of 2 laminations of cmc cut epoxy board and is a very tight fit in the lower 1/4 ply fuselage rails. The wing fitting is beginning to make sense now.

Trevor Rushton02/09/2014 21:49:47
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458 forum posts
181 photos

image.jpgLong view of the fuselage minus the top formers. The rear is drawn together and bolted; I was thinking that I may have to steam or slot the spruce longerons, but they seem sufficiently flexible as they are. I will complete the front section before I try properly.

cymaz02/09/2014 21:51:52
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8927 forum posts
1180 photos

Coming along well......onward and upwardlaugh

Trevor Rushton05/09/2014 22:31:00
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458 forum posts
181 photos

Okay, I watched the Tiger 9 again at the Shoreham show last week and now I have a question. All of the Tigers landed and then taxied back with down elevator. Now whenever I have taxied my cirrus moth and the smaller Tiger I have held in full up elevator to keep the tail on the ground. Am I missing something? Down elevator surely means it's more likely that the tail will want to lift under the effects of prop wash?

Gary Binnie05/09/2014 23:12:24
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518 forum posts
36 photos

Taxiing into wind, up elevator, downwind down elevator. The trim is set fully nose up for taxiing, elevator forces are quite high (not balanced) so actually holding up elevator in is not easy and I don't bother.

The wind strength and direction can have more effect than the propwash.

When the tailskid is on the ground the rear end is very heavy, bursts of throttle with rudder and forward stick lighten it and reduce the turn radius.

With a person in the rear cockpit a Tiger will not tip on its nose at low speed until the fuselage top longeron (cockpit door hinges) is quite well nose down.

Without a person in the rear cockpit the tail can be lifted about six feet in the air before it tries to tip over.

In this photo it is perfectly balanced, the centre of gravity is directly above the wheel axles.

Trevor Rushton05/09/2014 23:21:31
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458 forum posts
181 photos

Thanks for the explanation Gary; i'm still having trouble stopping the models from nosing over, but I understand what you are saying.

BTW, I missed AN last week - everything okay with her?

Trevor

Gary Binnie05/09/2014 23:39:12
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518 forum posts
36 photos

Yes, all good and safely in the hangar.

It's a bit different with models, the drag of grass acts like brakes on the wheels and things change dramatically!

There are Tigers with brakes, when these are fitted the wheels are moved subtly forward to try to prevent nose overs, The DH.82C (Canadian version) had brakes and a tail wheel as standard (cheating I reckon!).

Build is coming on nicely, my Flair Tiger is grounded for the need of a SLEC round fuel tank and some engine tuning problems.

cymaz06/09/2014 06:15:22
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8927 forum posts
1180 photos
Posted by Trevor Rushton on 05/09/2014 23:21:31:

Thanks for the explanation Gary; i'm still having trouble stopping the models from nosing over, but I understand what you are saying.

BTW, I missed AN last week - everything okay with her?

Trevor

Have you tried bring the main wheels forward a touch? I have the wheels 2/3 in front of the leading edge.

Trevor Rushton06/09/2014 22:13:29
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458 forum posts
181 photos

Thanks Gary and Cymaz

the wheels on the DB tiger are quite small and longer grass certainly does not help. The much larger ones on the 1/4 scale will be better I think.

Cymaz, I have had a look at the undercarriage on the db and I'd have to cut a few mm out of the front wire struts and join them again with a length of brass tube, but it's certainly possible. Moving the rear struts forward is not an option owing to the location of the hard points. I had been toying with the idea of some kind of skid, but yours is a much neater solution.

Trevor

Trevor Rushton09/09/2014 22:09:46
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458 forum posts
181 photos

image.jpgimage.jpgAssembled the elevator and rudder controls tonight. The cranks are made from epoxy board and are suitably robust. I am pleased with the feel of these components.image.jpg

ron thornhill29/09/2014 17:29:04
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84 forum posts
75 photos

Hi Trever I hope this build blog has not dried up. I know I am one of those people that read the blogs but do not contribute to them. I'm building the same kit, and wanted to ask if anyone out there has come up with a decent wing retaining system for transportation.

Ron.

Trevor Rushton01/10/2014 21:56:01
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458 forum posts
181 photos

Hi Ron

No, rest assured it s not dead! I am just taking a short break to complete a Skyways Kestrel to replace my recently departed Kyosho Calamoto. ( see separate build log). How far have you got with yours?

I have not really thought about the wing storage system yet; it's an interesting problem, Perhaps a pair of blue foam spacers that would slide in between the wings at an angle and could then be rotated vertically to wedge in position. The spacers could have horizontal holes through them (i.e. parallel with the chord) that could then slide over a frame containing 4 dowels. The arrangement could be contrived such as the rack containing the second set of wings slides over the same dowels. Does that make sense? I will doodle something to explain what I mean.

Trevor

Trevor Rushton01/10/2014 22:13:32
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458 forum posts
181 photos

image.jpg

Trevor Rushton01/10/2014 22:16:29
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458 forum posts
181 photos

My initial thoughts above. I guess that a piece of elastic could be used to clamp round the wings prior to un bolting them from the fuselage.one could add a foam spacer between each set of wings plus a similar top board that could be locked in position once it has been slid over the dowels.

Edited By Trevor Rushton on 01/10/2014 22:41:39

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